There's a pessimistic view that exists in science about how we haven't be contacted yet by aliens. One of the worries is that what if any advanced civilization eventually kills itself off.
I personally don't think we're being visited. You have to put a realistic perspective on things. We are a small binary solar system hanging out on one of the spiral arms of the Milkyway galaxy, destined to crash into the Andromeda galaxy many millions of years from now. We are pretty much a universe backwater.
What we need to do is grow up as a species, however there's just too many people interested in keeping us infants. These same people are our biggest worry when it comes to our survival in the future. We could be so much more advanced and further along in our understanding if it wasn't for this constant holding back.